Head Gasket leak?

[Dave WM]

got the replacement head super cleaned up, checked for warps again. One other thought, when I get ready to pull the old head off, I am going to rotate the crank 180 degrees off TDC. Then install the jam tool. I figure this will let me inspect the cylinder bore for possible cracks since that has not yet been ruled out (#6 piston will be at the bottom). I am 99% sure its #6 (either the head or the block) based on the test above so I can concentrate on inspection there. I was even thinking of some UV dye in the water and running it one more time, that way I can use the dye to help look for defects. Will run with the cap on so some pressure is built up after shut down. Granted the pressure will not be the same and in the reverse direction, but I figure it cant hurt.

Clearly I will have to remember to set the cam gear off 45 degrees as well, will use a grease pencil to mark the chain and gear.

Edited May 26, 2019 by Dave WM

[240260280]

Crack in head that opens due to exhaust heat?

[Zed Head]

That's some good diagnostic work there.  Magnaflux is the typical crack test method, I believe.  Looks like they've expanded their methods.  Might give you some ideas.

https://www.magnaflux.com/Magnaflux

I wonder how your engine would have run as a daily driver?  Pretty sure I've sen threads about gushing coolant and much discussion about "burping" the engines.  Maybe they just had cracked heads.  Ouch.

 

 

[Namerow]

8 hours ago, Zed Head said:

Magnaflux is the typical crack test method, I believe.  Looks like they've expanded their methods.

Magnaflux, the company, has attracted competitors over the years.  If you go this route, you (or your machine shop) may decide to use someone else's product.  There are two generic methods available.  One (UV-illuminated dye penetrant) is suitable for an aluminum part like your cylinder head.  The other (magnetization of the part) only works with parts made of ferrous materials (steel, cast iron, etc.).

Although I have no direct experience, I would hazard a guess that the dye penetrant check might deliver the best results if you pre-heat the head in an oven before spraying on the dye.  Not flaming hot, but maybe 250 degrees F.  Read the instructions that come with the kit first, though, to make sure whether this is a good idea or not.

[Dave WM]

well test today was not what I expected. started about 90f (ambient) engine started fine, #6 connected, NO gusher. This is the 1st time for that with a T stat installed. Now I am really confused.

there was  no water flowing (had the rad cap off with the meat thermo reading water temps (Plus I just put my palm up to the top of the rad). I was about 1 inch down from the bottom of the filler neck (about 1/2 inch of water covering the core estimated). Let it run fully expecting to see the gusher before the T stat opened. I stay quiet until the T stat opened right at 160f water begins to flow and stays there for a while, after about 5-10 min of idling it rose to about 175 on the T stat and held there. Water flowing everything normal.

Block test a few pumps, no change then had to break the vacuum by pulling it out and try again. It eventually did a very slight color change but seemed like I had to not have a tight seal least it suck itself down too hard to pump.

Bottom line is I am going to give it a rest, try again next week. If it does not gusher again I will have to ponder exactly what's going on. I guess I could have been a air pocket, but that does not explain the slight change in fluid color. I have the other head prepped and ready to go, so will prob swap it anyway now that I have read up on the swap being a nice performance mod. I still think I have a bit of a mystery on my hands.

I suppose the best course of action would be to simply take it  to a machine shop that can test for cracks in both the block and head and then get it machined as required (if ok). But at this point in time it seems that would be a waste of money since I really don't have an immediate need, and I really just wanted a spare. I too would like to see the engine in actual use ZH that would be a real world test since the only issue right now seems to be the chem test  fail.

 

[Dave WM]

next week I will do a full video of a cold start thru chem test so you guys can see what's going on (same test I did today), as I would like any observation on what I am doing and if doing something wrong. Might get a little boring waiting for things to heat up (why I did not do today, just figured it would gush and I would then go right to the head replacement and block inspection).

[Zed Head]

Maybe you had residual combustion byproducts in the block.  Or maybe you just have a small leak that shows on the test, but is not the cause of the gushing.  You're trying to assign two separate results to the same cause.  Might not be the case.

[Dave WM]

yes I see your point, could have been an air pocket super heating the water before the T stat opens (Gushing), AND a very small leak causing the chem test fail. Perhaps I finally got the air out (no gush) but still the leak enough to fail the chem test. Oh well will test again (I like repeatable results to test a theory) if the gushing is resolved but continues to fail test, perhaps the  working theory will be just a very small leak. I did NOT retorque the head bolts (felpro gasket) as that was the instructions.

 

[Dave WM]

series of test to be video recorded

1. cold engine, rad cap off, start monitor water temp with meat themo, check for gusher
2. engine warmed up and running check for exhaust gas in coolant
3. cold engine, rad cap off, #6 disconnected start monitor water temp with meat themo, check for gusher
4. engine warmed up and running check for exhaust gas in coolant

 

 

[Dave WM]

test completed, no gush, some gas, video to be posted later, but I wanted to show Jeff his gauge, I did not do a before shot, but it came out pretty nice. Must be earlier on, has the 140psi oil gauge

 

[Dave WM]

Test 1&2 combined.

 

[Dave WM]

did test 3&4 (disabled #6, cold start) exact same, still changing color. I am not going to bother trying it out on each cylinder, so will just move on to replace head. If that does not fix it I will pull the head and front cover so I can turn the crank and  CAREFULLY examine the block on all cylinders.

As a test I did pull air thru the fluid engine off rad cold, no change. Just wanted to me sure the chem could stay blue when being aeriated.